The present invention relates to a data transfer apparatus.
In recent years, there has been increasing need for the reliability of a network system. Along with the needs, a data transfer apparatus that performs data transfer between networks constituting the network system is required to maintain data transfer as much as possible.
The data transfer apparatus transfers data to an appropriate transfer destination according to a routing table held by the data transfer apparatus. The routing table stores transfer destination information that is used to transfer data to a next destination from each network.
In many data transfer apparatuses of the related art, a dedicated device called a transfer engine transfers data so as to increase the speed of data transfer. Generally, transfer engines designed and manufactured by professional semiconductor manufacturers are used because the transfer engine is a device that is required to exhibit high performance.
Transferring data at high speed requires that the transfer destination of data be searched in a short amount of time. In order to realize this, a memory that is used in the search of the transfer destination of data is disposed in the data transfer apparatus, and a transfer information base is stored on the memory. The transfer information base is a data format into which the routing table is converted. The data format allows the transfer engine to easily search for the transfer destination.
Typically, volatile memories are used for the memory that stores the transfer information base. Thus, the transfer information base stored on the memory is lost when the data transfer apparatus is stopped.
When a reboot of the data transfer apparatus occurs, the data transfer apparatus is required to generate the routing table again and to store the transfer information base which is generated by the conversion of the routing table on the volatile memory. Therefore, the data transfer apparatus of the related art has the problem that a time of a few tens of seconds to a few minutes is typically required until data transfer is resumed after the process as described above is completed.
The invention disclosed in JP-A-2013-187601 is known as means for resolving the above problem. In JP-A-2013-187601, disclosed is as follows: “A router includes a routing table storing unit that stores a routing table, which is destination information of a packet, and that is readable and writable any time and a transfer information base storing unit that stores a transfer information base, which is created on the basis of the routing table and which is correspondence information between a destination to which the packet can be transferred and addresses which are appropriate for sending the packet to the destination through a shortest path, and that is readable and writable any time. The router is provided with a search engine unit that searches for addresses to send the packet on the basis of the transfer information base, a power supply unit that supplies power to the routing table storing unit and the transfer information base storing unit, and a control unit that controls the power supply unit. At least one of the routing table storing unit and the transfer information base storing unit is a non-volatile memory. The control unit causes power to be supplied from the power supply unit to the non-volatile memory when the non-volatile memory operates and blocks supply of power to the non-volatile memory when the non-volatile memory does not operate.”
In the invention disclosed in JP-A-2013-187601, even if the packet transfer apparatus is rebooted, loss of the transfer information base is prevented because a non-volatile memory is used for the memory that is used in the search of the transfer destination of the packet. Thus, packet transfer can be quickly resumed.